What Makes an Ecohouse?

The definition of an ecohouse is an environmentally low-impact home, designed with sustainability in mind and built using materials and technology which reduce its carbon footprint and lower its energy needs. This seems both logical and necessary, the question is whether this standard can be approached in the UK, on a practical and financial basis.

The current situation, with the building of a few homes using German Passivhaus ideas is a laudable start, but if the industry really wants to make a difference to the environmental impact of its activities, a radical change of thinking is needed. It should no longer be acceptable to continue to build standard brick and mortar homes, apply cavity wall insulation and a few solar panels and expect that to be enough. Spread over 100 or more years the carbon footprint of the construction of an individual house may not look particularly high, but climate change is here, we no longer have 100+ years to put things right.

Materials used in standard house building are not obviously compatible with sustainable construction. For example, the use of concrete could be a major issue. Weight for weight it is the second largest quantity of material used in house building after bricks. Concrete is made from 10 to 15% Portland cement the manufacture of which requires a high input of energy resulting in one tonne of greenhouse gas emissions for every tonne of cement produced. Technologies are being researched to reduce this impact, including putting the CO2 back into the product, but these new materials are not yet widely available.

So, the question is, do we need to go back to mud floors and wattle and daub walls? Maybe the answer is another question; why not? We now know that we can build with wood without destroying the rainforests. Timber framed homes are increasing in popularity and in the right circumstances, other old technologies are also highly sustainable. Where hazel and willow grow easily, they can be coppiced for construction use as wattle and regrown rapidly. Daub is just any local, clay subsoil. For projects in the right area, such locally available materials can make building highly sustainable without going in for industrialised Passivehaus type technology. While some developers may baulk at the time/labour equation, not to mention having to retrain staff in unfamiliar techniques, maybe their priorities need to change.